Method of forming an apex filler

ABSTRACT

A method is provided for forming an apex filler including extruding a substantially linear elastomeric strip having a base and a pair of sidewalls converging from the base to an apex. The sidewalls of the elastomeric strip are then engaged with a nip presented by a pair of opposed frusto-conical rollers and a base support. The rollers are rotated to work the elastomeric strip whereby the base of the strip is rotated at a first linear speed, the apex is rotated at a second, greater speed and the sidewalls are rotated at linear speeds substantially proportional to the distance from the base to the apex, thereby forming an apex filler.

This is a divisional of application Ser. No. 07/791,043, filed on Nov.12, 1991, now U.S. Pat. No. 5,203,938, which is a divisional ofapplication Ser. No. 07/648,898, filed on Jan. 31, 1991, now U.S. Pat.No. 5,100,497, issued on Mar. 31, 1992.

TECHNICAL FIELD

The present invention relates to a method and apparatus for forming anapex filler anti/or applying an apex filler to a bead ring forincorporation in a vehicular tire. More particularly, the presentinvention relates to a method and apparatus for forming an apex fillerfrom an extruded ribbon of elastomeric material. Specifically, thepresent invention relates to a method and apparatus for forming a linearextrusion into an annular apex filler of the desired configuration andwhich may be separately, or simultaneously, applied onto an annular beadring, also by virtue of the method and apparatus according to thepresent invention.

BACKGROUND OF THE INVENTION

A tire has two, laterally spaced bead portions which define theinnermost diameter thereof. Each bead incorporates a metallic, ringsub-assembly which provides hoop strength and structural integrity tothe bead--i.e.: the rim engaging structure of the tire. Each bead alsonormally includes an apex filler in addition-to the metallic ringsub-assembly, because the combination assures a smooth transitionaljuncture between each bead and the adjacent side wall portion of thetire. To facilitate the manufacture of the tire, the ring subassemblyand the apex filler are generally provided as a composite assembly aboutwhich the plies of the tire may be wrapped.

One prior art method of fabricating the combined ring and apex fillerassembly applies a flat strip of elastomeric material along the innercircumference of a rubber coated, annular, ring sub-assembly and thenencapsulates the ring sub-assembly by wrapping the strip radiallyoutwardly about the wire ring sub-assembly. That portion of the stripwhich extends radially outwardly from the ring sub-assembly constitutesthe apex filler. This method is fraught with difficulties, particularlyin splicing the abutting ends of the wrapped strip. When the elastomericstrip is so wrapped to encapsulate the ring sub-assembly, the outercircumference of the material must stretch to accommodate the differencebetween the circumferential dimension of the ring sub-assembly and thecircumferential dimension at the radially outer periphery of the strip.This stretching induces stresses which produce warpage in the form ofdishing or scalloping along the radially outer portion of the resultingapex filler. This warpage is not constant front filler to filler, and ittherefore increases the difficulty of maintaining quality controlbetween successive tires employing bead assemblies made by this method.

Another known method of assembly applies an apex filler strip to arotating bead ring until the starting point of the apex filler strip isadjacent the point at which the apex filler strip was first applied tothe bead ring--approximately one revolution--at which time the apexfiller strip is severed. The combined ring and apex filler assembly isthen moved to a second processing station where a gripping andstretching apparatus engages the apex filler to close the ends. Thisalso results in stretching the radially outer circumference of the apexfiller strip more than that portion of the filler strip which has beenjoined with the bead ring. This stretching causes the same distortionproblems inherent to, and as described in conjunction with, thepreviously discussed prior art method.

SUMMARY OF THE INVENTION

It is, therefore, a primary object of the present invention to providean improved method and apparatus for forming an elastomeric strip intoan apex filler of substantially annular configuration without inducingdistortion to the resulting apex filler.

It is another object of the present invention to provide an improvedmethod and apparatus for forming an apex filler, as above, by working astrip of elastomeric material within the nip presented by opposedforming rollers to produce a substantially annular apex filler.

It is a further object of the present invention to provide an improvedmethod and apparatus for forming an apex filler, as above, by working alinear strip of extruded, elastomeric material within the nip presentedby opposed forming rollers to produce a substantially annular apexfiller.

It is a still further object of the present invention to provide animproved method and apparatus for forming an apex filler, as above,which may also be employed to apply the apex filler onto an annular beadring during the process of forming the apex filler.

It is yet another object of the present invention to provide an improvedmethod and apparatus for manufacturing and applying an apex filler, asabove, to an annular bead ring wherein the circumference of theelastomeric strip being formed into the apex filler is progressivelylengthened relative to the increasing radius thereof by virtue of theinteraction between the elastomeric strip and a pair of angularlyopposed forming rollers, while the apex filler is being simultaneouslyapplied to the outer periphery of the annular bead ring.

It is an even further object of the present invention to provide animproved method and apparatus for manufacturing and applying an apexfiller to an annular ring sub-assembly wherein the ring sub-assembly isrotatably mounted on a chuck assembly having selectively adjustablerollers to support the bead ring and also wherein a generallytriangular, elastomeric strip is extruded into a nip having theconfiguration desired for the apex filler, the nip being presentedbetween a pair of rotating frusto-conical rollers that engage theelastomeric strip at a progressively increasing linear speed betweenthat portion of the apex filler which engages the bead ring and theradially outermost extremity of the apex filler.

These and other objects of the present invention, as well as theadvantages thereof over existing and prior art forms, which will beapparent in view of the following detailed specification, areaccomplished by means hereinafter described and claimed.

In general, the present invention provides a method and apparatus forforming an apex filler, and which method and apparatus may also beuniquely adapted for applying an apex filler onto a bead ring withoutthe introduction of stresses at the outer edge of the apex filler.Apparatus embodying the concepts of the present invention for forming anapex filler preferably works in conjunction with an extruder whichpresents a linear strip of elastomeric material having a generallytriangular cross-section with a base and a pair of converging sidewalls.A pair of opposed, frusto-conical forming roller means present a niptherebetween. Means are provided to rotate the frusto-conical formingroller means. Rotation of the forming roller means allows the nipfrictionally to engage the elastomeric strip that is fed into the nip.The interaction between the elastomeric strip and the nip effects rotarymotion of the elastomeric strip and increases the circumferential lengthof the elastomeric strip proportionally to the radial distance outwardlyfrom the base thereof.

The aforesaid apparatus permits an apex filler to be formed according toa method whereby a linear, elastomeric strip having a base and a pair ofsidewalls which converge from the base to an apex is extruded. Thesidewalls of the elastomeric strip are engaged with a nip presented by apair of opposed, frusto-conical rollers. The rollers are rotated to workthe elastomeric strip within the nip and thereby effect rotation of thebase at a first linear speed, the apex at a second and greater linearspeed and the sidewalls at linear speeds substantially proportional tothe distance from the base to the apex.

One exemplary embodiment of the apparatus, which embodies the conceptsof the present invention and which is adapted for use in the manufactureof bead ring assemblies for eventual use in tire making is deemedsufficient to effect a full disclosure of the subject invention, isshown by way of example in the accompanying drawings and is described indetail without attempting to show all of the various forms andmodifications in which the invention might be embodied; the inventionbeing measured by the appended claims and not by the details of thespecification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation depicting an apparatus embodying the conceptsof the present invention for forming an apex filler and for applying anapex filler so formed to a bead ring sub-assembly for a pneumatic tire,the apparatus capable of being operated according to the method of thepresent invention;

FIG. 2 is an enlarged, frontal elevation of the apparatus depicted inFIG. 1;

FIG. 3 is an enlarged area of FIG. 1 depicting a mounting chuck employedto grip the bead ring sub-assembly;

FIG. 4 is an enlarged frontal elevation of the apex filler formingmechanism depicted in FIGS. 1 and 2, the forming mechanism being shownin the open position which permits operatively positioning a bead ringsub-assembly between the opposed roller means in the forming mechanismor removing a completed apex filler or, in the embodiment depicted,removing a completed tire bead assembly;

FIG. 5 is a view similar to FIG. 4 but depicting the forming mechanismin the closed position, is it would be disposed to form an apex filler,or in the embodiment depicted to form the apex filler whilesimultaneously applying it to a bead ring sub-assembly--as such, saidview is taken substantially along line 5--5 of FIG. 1;

FIG. 6 is also an enlarged area of FIG. 1 but with one of the formingrollers broken away to the interaction between the other forming rollerand a gripping chuck employed to present a bead ring sub-assembly to theforming mechanism;

FIG. 7 is a vertical section taken substantially along line 7--7 of FIG.6;

FIG. 8 is an enlarged, horizontal section taken substantially along line8--8 of FIG. 6 to depict the forming mechanism, and particularly therollers in bottom plan;

FIG. 9 is a partial side elevation of a tire bead assembly whichcomprises a bead ring sub-assembly to which an apex filler has beenapplied according to the method, and by the apparatus, of the presentinvention;

FIG. 10 is an enlarged section taken substantially along line 10--10 ofFIG. 9; and,

FIG. 11 is a view similar to FIG. 10 but depicting an alternativedisposition at which the apex filler may be applied to a bead ring inaccordance with the concepts of the present invention.

DESCRIPTION OF AN EXEMPLARY EMBODIMENT

Referring to the drawings, wherein like characters represent the same orcorresponding parts throughout the several views, a novel and uniqueapex filler forming mechanism 10 is shown and described in combinationwith an apparatus 11 for assembling pneumatic tire bead assemblies 12,which apparatus employs the apex filler forming mechanism 10 to apply anapex filler 13 to a bead ring sub-assembly 14 which is best seen inFIGS. 9 and 10. The composite bead assembly apparatus, which includesthe forming mechanism 10 and the apparatus 11 for applying the apexfiller 13 to the bead ring sub-assembly 14 is designated generally bythe identifying numeral 15. With specific reference to FIGS. 1 and 2,the bead assembly apparatus 15 rests on a base 16 from which a post 18extends generally upwardly. A chuck supporting assembly 19 is rotatablysupported on the post 18, and the chuck supporting assembly 19 presentsthree radially extending arms 20, each of which terminates in a mountingchuck 21.

In the detailed description which follows, a particular structuralmember, component or arrangement may be employed at more than onelocation. When referring generally to that type of structural member,component or arrangement a common numerical designation shall beemployed. However, when one of the structural members, components orarrangements so identified is to be individually identified it shall bereferenced by virtue of a letter suffix employed in combination with thenumerical designation employed for general identification of thatstructural member, component or arrangement. Thus, there are at leastthree arms which are generally identified by the numeral 20, but thespecific, individual arms are, therefore, identified as 20A, 20B and 20Cin the specification and on the drawings. This same suffix conventionshall be employed throughout the specification.

The chuck supporting assembly 19 is rotatable, as by motor 17,sequentially to index the arms 20 between three successive stations 22.As best presented in FIG. 1, the arm 20A is located at the loadingstation 22A. Arm 20B is located at the assembly station 22B, and arm 20Cis located at the unloading station 22C. At the loading station 22A abead ring sub-assembly 14 is installed on the mounting chuck 21A by aconventional, swing arm loading mechanism 23. At the assembly station22B an apex filler 13 is applied to the bead ring sub-assembly 14. Atthe unloading station 22C the completed tire bead assembly 12 is removedfrom the mounting chuck 21C by a conventional, swing arm unloadingmechanism 24 and placed on a storage rack, not shown.

The radially extending arms 20 of the chuck supporting assembly 19 aremaintained at the successive stations 22 to which they are indexed bylocking mechanism 25. As best seen in FIGS. 2 and 7, the lockingmechanism 25 includes a pin 28 and an actuator 29 presented from thecantilevered extension arm 30 which extends outwardly from the supportpost 18 to be received within a detent recess 31 provided in the chucksupporting assembly 19.

Accordingly, when an arm 20 is properly located at a station 22 theactuator 29 is energized, in a conventional manner, to extend the pin 28into the detent recess 31, thereby preventing the arms 20 frominadvertently being rotated. When the procedures scheduled for eachstation are completed the pin 28 is retracted from the detent recess 31by de-energizing the actuator 29, thereby permitting unimpeded rotationof the chuck supporting assembly 19.

Because an apex filler 13 manufactured according to the concepts of thepresent invention may constitute an article of commerce, the apexforming mechanism 10 shall be detailed before describing the apex fillerapplying apparatus 11 in the context of the overall, composite, beadassembly apparatus 15. Thus, when an arm 20 is disposed at the assemblystation 22B, a bead ring sub-assembly 14 is supported for rotation onthe mounting chuck 21B, and the bead ring sub-assembly 14 is grippedbetween a pair of opposed and rotatable rollers 33A and 33B which, asbest seen in FIGS. 5 and 7, may be frusto-conical in shape to define anip 35 therebetween. As will become apparent, the cross sectionalconfiguration of the nip 35 is virtually identical with cross sectionalshape to which the apex filler 13 is to be formed. Each roller 33 may berotated by a conventional drive train which includes a motor 36, a chaindrive 37 and a gear reducer 38. In the alternative, the opposed rollers33A and 33B may be interconnected by conventional gearing to maintainthe proper speed relationship therebetween while being driven by asingle power source, such as an electric motor.

As shown, the nip 35 may be formed by a compound, frusto-conical outersurface on each of the opposed rollers 33A and 33B. That is, the outersurface on each roller 33 may have a first, frusto-conical portion 39which serves grippingly to engage the radially outer corners 41A and 41B(FIG. 10) of the bead ring sub-assembly 14, and a second, frusto-conicalportion 40 which serves not only to grip but also workingly to form theapex filler 13, as will be hereinafter more fully described.

With respect, first, to surface portion 39 of the rollers 33 it shouldbe appreciated that whereas the representative bead ring sub-assembly 14is depicted as being rectilinear, it could, as well, have anothergeometric cross section--i.e.: hexagonal, octagonal or even circular, tomention a few. The point is that the surface portions 39 of the opposedrollers 33 should have whatever configuration is necessary to effect thenecessary driving engagement with the flanks of the sub-assembly14--those flanks being the corners 41 in the rectilinear configurationdepicted.

In any event, the use of the compound, frusto-conical portions 39 and 40on the opposed rollers 33A and 33B readily provides such cross sectionalconfigurations for the tire bead assemblies 12 and 112 depicted in FIGS.10 and 11, respectively. It should be appreciated, however, that thepresent invention is fully capable of producing apex fillers 13 having awide variety of cross sectional configuration. To that end it must beunderstood that the opposed forming rollers 33 need not form the nip 35with only conical surfaces. The nip 35 may, for example, be formed byoppositely disposed, curving surfaces, one of which may be convex andthe other of which may be concave. Irrespective of the shape employed todefine the nip, the opposing surfaces must be configured to providecorresponding points on each which are the same distance from therespective axes about which the forming rollers presenting those opposedpoints rotate. As a result, contact of the rollers with the apex fillerbeing formed will be linear. That is, the speed of the nip surface atany point on one forming roller will be exactly equal to the speed ofthe corresponding point on the opposed roller so that the materialbetween those points is not subjected to working transversely of the nip35, and yet each successive point along the radius of each roller 33moves at a progressively increasing rate radially outwardly of theforming rollers. In this manner substantially stress free differentialelongation is maintained as the elastomeric material is formed into anapex filler of the desired cross sectional configuration.

To return to the description of the configuration for an exemplary nip35 the frusto-conical portions 39 and 40 may well be formed as narrowcylindrical lands along the circumference of the rollers 33, if desired.

With continued reference to FIG. 1, an elastomeric strip 42 is forcedfrom a conventional extruder 43 and may pass through conventionalaccumulators 44 and an in-flight cutter and feeder 45 which directs thestrip 42 into the nip 35. After the elastomeric strip 42 is formedwithin the nip 35 the resulting apex filler passes between a pluralityof guide rollers 48 (FIGS. 4 and 8). The rollers 48 provide guidance tothe apex filler 13, thereby assuring that the base 49 thereof ismaintained in alignment with the outer circumferential surface 46 (FIG.10) of the bead ring sub-assembly 14 as they leave the nip 35. Therollers 48 may also be advantageously employed to guide the apex filler13 out of the nip 35, even if the apex filler 13 is not simultaneouslyapplied to a bead ring sub-assembly 14.

As the elastomeric strip 42 is worked within the nip 35 presentedbetween the opposed rollers 33, the radial outer edge 50 of the strip 42is forced through the nip 35 at a faster linear speed than is the base49 of the strip 42. In fact, the differential speed of the strip 42,considered incrementally from the base 49 to the radially outer edge 50,is linear. Thus, each incremental portion of the elastomeric strip 42from the base 49 to the radially outer edge 50 thereof is forced totravel a greater distance than the base 49 and is therefore elongatedrelative to the base 49. Accordingly, the circumferential dimension ofthe radially outer edge 50 is greater than that of the base 49 due tothe forced, continuous differential elongation of the elastomeric strip42 in the radial direction, and the linear elastomeric strip 42 whichenters the nip 35 is thereby formed into an annulus with the base 49establishing an inner circumferential surface which is tack-bonded tothe outer circumferential surface 46 of the bead ring sub-assembly 14.In other words, the resulting apex filler 13 is lengthened, orpermanently stretched, differentially between the base 49 and theradially outer edge 50 as the strip 42 is worked between the rollers 33.Therefore, the resulting apex filler 13 does not have the tendency tobow, buckle, fold, dish or scallop along the radially outer edge 50, asoccurs with typical prior art apex fillers.

It should be understood, however, that the working does not stretch thebase 49 of the elastomeric strip 42. The linear speed of thefrusto-conical surfaces 39, where contact is made with the corners 41,is virtually identical with the linear speed of the immediately adjacentfrusto-conical surface portions 40 on the rollers 33. Thus, there is aninsufficient speed differential between the outer cylindrical surface 46of the bead ring sub-assembly 14 and the base 49 of the elastomericstrip 42 to cause one to move relative to the other. Therefore, thesesurfaces are tack-bonded together without stresses arising therebetween.

For a more detailed description of the apex filler forming mechanism 10,the rollers 33A and 33B are mounted on respective housings 51A and 51B,and the previously identified electric motors 36, chain drives 37 andgear reducers 38 are supported from the housings 51. Drive shafts 52Aand 52B extend outwardly from the corresponding gear reducers 38A and38B to rotate the rollers 33A and 33B, respectively.

The housings 51A and 51B are pivotally supported from a pair oflaterally spaced mounting arms 53A and 53B (FIG. 1) which extendperpendicularly outwardly from a positioning bracket 54 that is itselfmounted for translational movement toward and away from a cantileveredsupporting beam 55 that extends perpendicularly outwardly from the post18. The pivotal support between the housings 51A and 51B and themounting arms 53A and 53B may be effected by pin connections 56A and56B. The translational movement of the positioning bracket 54 relativeto the supporting beam 55 may be effected by apex diameter adjustmentassembly 60. The apex diameter adjustment assembly 60 employs a pair ofthreaded members 61A and 61B which are operatively connected between thepositioning bracket 54 and the supporting beam 55 and are adapted to besimultaneously driven by a conventional electric motor 62. Selectiverotation of the threaded members 61 effects translational movement ofthe positioning bracket 54 with respect to the fixed supporting beam 55that will raise and lower the apex filler forming mechanism 10.

As best seen in FIG. 5, the threaded members 61 are each rotatablymounted in a thrust bearing assembly 63 which is secured to thesupporting beam 55. The threaded shaft portion 64 of each member 61 ismatingly received within a threaded collar 65 which is secured to thepositioning bracket 54. In as much as the two threaded members 61A and61B are to rotate in unison, they may be connected, as by a chain drive66, to the single, electric motor 62.

As will become hereinafter more fully apparent, this selectivepositioning of the forming mechanism 10 which can thus be achieved bythe apex diameter adjustment assembly 60, permits the forming mechanism10 to be used for the manufacture of apex fillers 13 and tire beadassemblies 12 in a multitude of diameters. Typically, tire beadassemblies 12 having an inside diameter in the range of from about 13inches (33.02 cm) to about 19 inches (48.26 cm) can be made on a singleforming mechanism 10.

In order to open and close the apex filler forming mechanism 10--asrequired to insert a bead ring sub-assembly 14 and to remove a completedtire bead assembly 12, or perhaps an annular apex filler 13--one mayselectively pivot the housings 51A and 51B about the pin connections 56.Specifically, a pair of drive cylinders 70A and 70B may be operativelyconnected between the respective housings 51A and 51B and thepositioning bracket 54 to effect the aforesaid pivotal movement requiredto open and close the apex filler forming mechanism 10. A first clevis67 on each cylinder 70 may be pivotally secured to the positioningbracket 54, and a second clevis 68, which is presented from the pistonrod 69 extending outwardly from each cylinder 70, may be pivotallyattached to the appropriate housing 51.

Control over the extent to which the forming mechanism can open andclose may be effected by adjustment rods 71. One end of each adjustmentrod 71 presents a clevis 72 that may be attached to one of the housings51. The opposite end of each rod 71 may be provided with an adjustmentmeans 73, such as a nut, that can be rotated to establish the desiredlength for each rod 71. The length of the adjustment rods 71 permits theapex filler forming mechanism 10 to be closed only to a predeterminedextent, which results on the desired angular disposition of the opposedrollers 33, and thereby the frusto-conical surface portions 39 and 40thereon. The drive cylinders 70 thereby serve to pivot the housings 51of the forming mechanism 10 from the open position represented in FIG. 4to the closed position represented in FIG. 5, and vice versa. In theopen position, the housings 51 are separated sufficiently to permit theremoval of an completed tire bead assembly 12 from between the rollers33 and thereafter to permit a bead ring sub-assembly 14 to be positionedbetween the rollers 33. As best seen in FIG. 5, the adjustment means 73engage the positioning bracket 54 to determine the extent to which therollers 33 can approach each other in the closed position of the apexfiller forming mechanism 10.

Because the apex diameter adjustment assembly 60 is capable of beingopened and then closed to the degree determined by the adjustment rods71, it is necessary to provide a means by which to effect lateraladjustment for the axes "X" and "Y" of the drive shafts 52A and 52B,respectively. This result can, for example, be accomplished by mountingeach motor 36, and the gear reducer 38 associated therewith, on aslotted plate 57 that is slidable laterally along the housing 51 withinwhich that motor 36 and gear reducer 38 is mounted. Mounting screws 58,which extend through the slotted plates 57, secure the plates 57 to thehousings 51, and at least one set screw 59 serves to permit fineadjustment in the lateral position of each slotted plate 57, and thusthe axes "X" and "Y" of the drive shafts 52.

The adjustments provided by the heretofore described structure permitsthe forming mechanism 10 to fabricate apex fillers 13 having a fairlywide range of cross sectional configurations. In addition, the aforesaidforming mechanism 10 may also fabricate tire bead assemblies 12 having awide range of bead diameters and cross sectional dimensions without theneed to interchange components. Changing the height of the apex fillers13 is accomplished simply by exchanging rollers 33.

As is well known to the art, the bead ring sub-assembly 14 may have anumber of configurations, but the drawings represent a typicalconstruction wherein each bead ring sub-assembly 14 comprises a volutewound metallic ribbon 74 that is encased by a coating of uncuredelastomeric material 75 in order to effect a joinder not only betweenthe successively wound layers of the ribbon 74 forming the bead ringsub-assembly 14 but also between the ring sub-assembly 14 and the apexfiller 13 without the need to employ special adhesives. In order tosimplify the disclosure the bead ring sub-assembly 14 was depicted ashaving a rectilinear cross section, and the apex filler was depicted ashaving a cross sectional configuration of an isosceles triangle. It mustbe understood, however, that the present invention is not limited tothat specific configuration. For example, an alternative configurationis depicted in FIG. 11. In FIG. 11 the tire bead assembly 112 utilizesall apex filler 113 having the cross sectional configuration of ascalene triangle. The base 149 of the apex filler 113 also engages theouter circumferential surface 146 of the bead ring sub-assembly 114 butthe radially outer edge 150 of the apex filler 113 is laterally offsetfrom the position it occupies in tire bead assembly 12. This tire beadassembly 112, and its components, may be manufactured with the sameprocesses that are used to manufacture the tire bead assembly 12, andits components. The shape of the apex filler 13, or 113, is determinedby the configuration, and disposition, of the frusto-conical surfaceportions 39 and 40 on the rollers 33. A wide range of apex fillers canbe shaped by the forming mechanism 10. The ability to provideindependent, angular adjustment of each housing 51A and 51B, togetherwith the ability to select the desired cross sectional configuration ofthe rollers 33 will allow the apex filler to be formed within the widerange of adjustments available.

As best seen in FIGS. 1, 3, 6 and 7, each mounting chuck 21 is supportedfrom its respective arm 20 on the chuck supporting assembly 19.Specifically, each mounting chuck has an extension arm 76 that may beattached at selective radial locations along one of the selected radialarms 20. Each extension arm 76 is maintained in the desired radialdisposition relative to the arm 20 to which it is secured by a pair ofalignment blocks 78 which extend perpendicularly outwardly from each arm20 to be received within a slot 79 which penetrates the radially innerend portion of the extension arm 76. The extension arm 76 is thensecured to the radial arm 20 by a fastening means in the nature of a capscrew 80 which penetrates the slot 79 to be received within a threadedbore 81 in the arm 20. The precise radial position of the extension arm76 on the arm 20 is established by a locating pin 82 which isselectively disposed in one of a plurality of locating apertures 83which a recessed into the arm 20. The particular locating aperture 83selected is determined by the diameter of the apex filler and/or tirebead assembly 12 that is to be manufactured.

A chuck frame 85 is secured to the radially outer end portion of eachextension arm 76. The chuck frame 85 has a cylindrical portion 86 (FIG.7) which extends perpendicularly outwardly from the extension arm 76 andterminates in an annular intermediate ring 88. A rotary solenoid 89 maybe received within the hollow interior of the cylindrical portion 86 andbe anchored to the chuck frame 85 operatively to rotate a drive disk 90.Each mounting chuck 21 employs a plurality of drive arms 91, and theradially inner end of each drive arm 91 is pivotally connected to thedrive disk 90, as by a collar clamp 92. The medial portion of each drivearm 91 has longitudinally extending slot 93. The radially outer portionof each extension arm 76 presents a bead ring support assembly 94 thatis rotatable mounted thereon.

A collar clamp 95 is received through the slot 93 in each drive arm 91to be anchored within the intermediate ring 88. Each collar clamp 95provides a fulcrum and a means by which to guide the generally radiallyinward and outward movement of the drive arms 91, which is effected bythe attachment of the inner end portion of each drive arm 91 to thedrive disk 90.

As best seen in FIG. 7, each collar clamp 92 has a pin 96, a hat-shapedbushing 98 and a collar 99. The bushing 98 provides an anti-frictionsurface between the drive arm 91 and the pin 96 and also between thedrive arm 91 and the drive disk 90. The collar 99 is mounted on the pin96 and limits the linear motion of the drive arm 91 along the bushing98. Each collar clamp 95 includes a pin 100, a bushing 101, a washer 102and a collar 103. The bushing 101 provides an anti-friction interfacebetween the drive arm 91 and the pin 100 as the drive arm 91 is movedlinearly relative to the pin 100. The collar 103 and the washer 102restrain the drive arm 91 from inadvertently disengaging the pin 100.

Each bead ring support assembly 94 is comprised of a roller 104, and ahat-shaped cover 105 that is supported on, and circumscribes, the roller104. Each roller 104 is supported on a threaded stem 108. The threadedstem 108 extends through an aperture 109 in the drive arm 91 and issecured thereto by a fastener 110.

A positioning and support roller assembly 115 is secured to theintermediate ring 88 and extends radially outwardly therefrom. Theroller 116 in the assembly 115 is mounted on an offset base 118 which issecured to the intermediate ring 88 by a pair of fasteners 119 in amanner permitting radial adjustment of the roller 116. Typically, theaccommodation for this adjustment may well entail the provision of aslot 117 in the base 118 through which the fasteners 119 are received.When properly adjusted, the roller 116 is positioned at a radius suchthat the bead ring sub-assembly 14 will be supported thereby at thedesired location relative to the nip 35. Thus, as the elastomeric strip42 is forced into abutment with the radially outer surface 46 of thebead ring sub-assembly 14, the radially inner surface 120 of thatsub-assembly 14 is supported to prevent radially inward movementthereof. Therefore, sufficient force can be exerted at the interfacebetween the elastomeric strip 42 and the bead ring sub-assembly 14 tocause tack-bonding of those components.

In order to facilitate ease of loading of the bead ring sub-assembly 14and unloading of a completed tire bead assembly 12, respectively, ontoand off of the chucks 21, the support rollers 94 presented from theradially outer ends of the drive arms 91 can be withdrawn from theradial position established by the positioning and support roller 116 towhat shall be identified as the un-clamped position, as depicted in FIG.3. This withdrawal is accomplished by rotating the drive disk 90clockwise relative to the fixedly positioned intermediate ring 88. Thisrotation can be accomplished by any conventional means such as anelectric stepping motor, a fluid motor or a rotary solenoid. Suchdevices are believed to be well known to those skilled in the art as arethe methods of mounting and powering such devices. In the exemplaryembodiment depicted, the drive disk 90 is connected to an output shaft121 (FIG. 7) of a conventional rotary solenoid 89. The rotary solenoid89 is disposed within the hollow interior of the cylindrical portion 86of the chuck frame 85, and a plurality of threaded stems 123 extendoutwardly from the frame 124 of the rotary solenoid 89 to be receivedthrough openings 125 provided in the chuck frame 85. A nut 126 isthreaded on each stem 123 to secure the rotary solenoid 89 to the chuckframe 85.

The rotary solenoid 89 is selectively activated to rotate the drive disk90 counterclockwise to effect the expanded, or clamping position, of thechuck 21 (FIG. 6), and conversely the rotary solenoid may be deactivatedto rotate the drive disk 90 clockwise to effect the contracted, orreleasing position, of the chuck 21 (FIG. 3).

The amount of counterclockwise rotation of the drive disk 90 asdetermined by the diameter of the bead ring sub-assembly 14 receivedtherein As the diameter of the bead ring sub-assembly 14 increases, theroller assemblies 94 on the drive arms 91 will be extended furtheroutwardly. The maximum diameter that can be achieved by the chuck 21 isestablished when the drive arms 91 are disposed radially from the centerof the drive disk 90.

The drive arms 91 are retracted--the chuck is un-clamped--at theunloading station 22C. The drive arms 91 are extended--i.e.: the chuckis clamped--at the loading station 22A and the chuck 21 remains clampedat the assembly station 22B.

In order that the elastomeric strip 42 can be cut to the proper length,a conventional sensor, not shown, may be positioned to read the presenceof the apex filler 13 at a specific position about the circumference ofthe chuck 21. As the opposed rollers 33 shape the elastomeric strip 42into the apex filler 13 and apply the shaped apex filler 13 to the beadring sub-assembly 14, the leading edge 128 of the elastomeric strip 42will pass the sensor. This signals a conventional hot knife, disposed inthe in-flight cutter and feed assembly 45, to cut the elastomeric strip42 such that the proper length is provided and the apex filler 13 willnot need to be stretched to complete the splice 129. The exactpositioning of the sensor can be determined for each size tire beadassembly 12 that will be manufactured on the bead assembly apparatus 15.The sensor used may be a conventional device such as an optical,electrical or fluidic proximity sensor. These devices are well knownsuch that a more elaborate discussion of them is not believed necessaryat this point.

After the tire bead assembly 12 is completed at station 22B, the chucksupporting assembly 19 is rotated to:

1. present the completed tire bead assembly 12 at station 22C to beunloaded;

2. allow a new bead ring sub-assembly 14 to be loaded on the chuck 21that is presented at the loading station 22A; and,

3. present a bead ring sub-assembly 14 at station 22B where an apexfiller 13 can be applied thereto.

This completes the assembly cycle which may be repeated as often asnecessary to provide the desired number of tire bead assemblies 12.

SUMMARY

A linear, elastomeric strip 42 is extruded from the extruder 43 and isdirected through an accumulator 44--which may be in the configuration ofthe commonly designated "dancer" or "festoon"--from which the strip 42is delivered, by an in-flight cutter and feeder assembly 45, to the nip35 presented between a pair of opposed, rotating rollers 33. While theelastomeric strip 42 is between the rollers it is worked from a linearto an annular configuration. Because the rollers 33 provide anincrementally increasing speed differential from the base 49 to theradially outer edge 50 of the elastomeric strip 42 within the nip 35 theouter edge 50 has a greater linear speed than the base 49. Theelastomeric strip 42 is worked by that speed differential. Because thespeed differential increases proportionally to the distance between thebase 49 and the outer edge 50, the strip 42 is stretched, or elongated,proportionally to that speed differential. Thus, the present inventionforms an apex filler 13 that does not have internal stresses which causeit to bow, buckle, fold, dish or scallop. Simply stated the annular apexfiller 13 is of the correct circumferential length at all radialpositions thereof.

When the apex filler 13 is being worked it may also be applied to theradially outermost surface 46 on a bead ring sub-assembly 14. In thatsituation the radially inner periphery 49 of the elastomeric strip 42which becomes the apex filler 13 is forced into abutment with theradially outer surface 46 of the bead ring sub-assembly 14. Because boththe bead ring sub-assembly 14 and elastomeric strip 42 have a tacky,rubber surface they are readily tack-bonded to each other by thepressure with which the apex filler 13 is applied to the bead ringsub-assembly 14.

The elastomeric strip 42 is cut by the in-flight cutter and feederassembly 45 when the proper length has been extruded, which occurs whenthe linear length of the elastomeric strip 42, measured along the base49, is equal in circumferential dimension of the bead ring sub-assembly,measured along the radially outer surface 46 thereof. Because it isundesirable to stop the extrusion process, an accumulator 44 is used toaccommodate the continued extrusion while the remainder of theelastomeric strip 42 is applied to a bead ring sub-assembly 14. Byproviding a loading station 22A, an assembly station 22B and anunloading station 22C on a rotatable chuck supporting assembly 19,minimum wait time occurs between the cutting operation and thepositioning of a new bead ring sub-assembly 14 at the assembly station22B. Thus, the accumulator 44 need only accommodate a minimum length ofthe extrudate, particularly when the extrusion time is established to bevery close to the assembly time.

The mounting chucks 21 are provided to permit rapid loading of the beadring sub-assembly 14 and unloading of the completed tire bead assembly12. The mounting chucks 21 also support the bead ring sub-assembly 14for rotation during the application of the elastomeric strip 42 to thebead ring sub-assembly.

The foregoing description of the exemplary embodiments of not only theapex filler forming mechanism 10, which may be an independent article ofcommerce, but also the apex filler applying apparatus 11, which isparticularly adapted to operate in conjunction with the apex fillerforming mechanism 10, has been presented for the purposes ofillustration and description. The description of the exemplaryembodiments is not intended to be exhaustive or to limit the inventionto the precise form disclosed. Obvious modifications or variations arepossible in light of the above teachings. The embodiment was chosen anddescribed to provide the best illustration of the principles of theinvention and its practical application to thereby enable one ofordinary skill in the art to utilize the invention in variousembodiments and with various modifications as are suited to theparticular use contemplated. All such modifications and variations arewithin the scope of the invention as determined by the appended claimswhen interpreted in accordance with the breadth to which they arefairly, legally and equitably entitled.

As should now be apparent, the present invention not only teaches amethod and apparatus for forming an elastomeric strip into an apexfiller of substantially annular configuration without inducingdistortion in the resulting apex filler as well as a method andapparatus for applying such an apex filler to a bead ringsub-assembly--both methods and apparatus embodying the concepts of thepresent invention--but also that the other objects of the invention canlikewise be accomplished.

We claim:
 1. A method of forming an apex filler comprising the stepsof:extruding a substantially linear, elastomeric strip having a base anda pair of sidewalls converging from the base to an apex; engaging thesidewalls of the elastomeric strip with a nip presented by a pair ofopposed frusto-conical rollers and a base support to engage the base ofthe elastomeric strip; and rotating the rollers to work the elastomericstrip within the nip and at the same time to effect rotation of the baseat a first linear speed, the apex at a second, and greater, linear speedand the sidewalls at linear speeds substantially proportional to thedistance from the base to the apex.
 2. A method of forming an apexfiller comprising the steps of:extruding a substantially linear,elastomeric strip having a base and a pair of sidewalls converging fromthe base to an apex; engaging the sidewalls of the elastomeric stripwith a nip presented by a pair of opposed frusto-conical rollers and abase support to engage the base of the elastomeric strip; and elongatingthe elastomeric strip in a radially differential manner as determined bythe frusto-conical rollers to form an annulus with the base thereofhaving a first linear dimension and the apex of the elastomeric striphaving a second linear dimension sufficiently greater than the firstlinear dimension to form a substantially continuous annulus.